JMR,
Just a quick post to let you know I haven't forgotten about the '39 and '40 almanacs. I've been a little busy, mostly with the weather around here. We got 10+ inches of rain in less than a week, set the all time record for any month and we still have half a month to go. Gonna NEED a sub if this keeps up!
Your mathematical travails look similar to mine, about half the time I get a LOP that seems wrong,

then go back and find a simple error and it works out.
Don's right, almost as bad as doing your taxes. (and we're doing this for fun?)
Cheers,
Mike